capacity, due to its popularity this assay is commonly known as the
total phenols (or phenolic) assay and it has become a routine assay in
studying phenolic antioxidants (Huang, Ou, & Prior, 2005; Prior, Wu,
& Schaich, 2005). To determine the content of total flavonoids, these
compounds were precipitated using formaldehyde, which reacts
with C-6 or C-8 on 5, 7-dihydroxy flavonoids. The condensed products
of these reactions were removed by filtration and remaining
non-flavonoid phenols were determined according to the previously
mentioned procedure for the determination of total phenol
content. Flavonoid content was calculated as the difference between
total phenol and non-flavonoid content. Gallic acid was used as the standard
and the resultswere expressed asmg gallic acid equivalents (GAE)/g
of sample. All measurements were performed in triplicate.